This invention relates to a fluid or hydrodynamic coupling, and more particularly, it is concerned with a method and apparatus for fitting a multitude of blades to the inner surface of the outer shell of a turbine wheel for the fluid coupling made of sheet metal stamping.
The fluid coupling has, as its component elements, a turbine wheel, a pumping wheel, a stator wheel, an input shaft, an output shaft, a unidirectional clutch, and so forth. Of these component elements, the turbine wheel and the pumping wheel are both constructed with an outer shell, an inner core, and a plurality of blades or vanes fixedly secured between these two component members. While it is desirable from the standpoint of reduction in the manufacturing cost that these turbine wheel and pumping wheel be formed with a sheet metal, there inevitably arises, in this case, such a problem that fixing of the blade on the outer shell is particularly difficult. For example, when the blade and the outer shell are partially welded, there is caused a resistance in the flow of the fluid due to protrusion of beading into the inner surface of the outer shell, or distortion of the outer shell caused by welding, with the result that the function of the fluid coupling becomes impaired.